In recent years, users generally use image projecting device and white-board devices for meetings, and they write outcome of the meeting on a viewing surface of a white-board device on which an image has been displayed via an image projecting device. For such purposes, well known are products, which combine a projected image, projected by the image projecting device, with a scanned image on the viewing surface of the white-board device, and said products print out combined images, whereby various technologies have been disclosed for aligning the positions of the projected image and the scanned image.
For example, Unexamined Japanese Patent Application Publication 2001-16384 discloses a technology in which a position mark, projected by the image projecting device, is used for a positioning standard, being marked on the screen, concerning an apparatus for combining projected image data on an image projecting device, with the image data on a screen of an electronic viewing board.
Further, unexamined Japanese Patent Application Publication 9-51423 discloses technology in which an image applied to an overhead projector is marked on a screen as a positioning standard, concerning an apparatus for combining the projected image data on the overhead projector with the image data on the screen of an electronic viewing board.
Still further, Unexamined Japanese Patent Application Publication 9-51424 discloses technology in which light rays, existing on the side of projected images on an overhead projector, are detected by an optical sensor mounted on an electronic viewing board, so that the projected image data are aligned onto the screen of the electronic viewing board, concerning an apparatus for combining the projected image data on the overhead projector with image data on the screen of an electronic viewing board.
In order to combine the projected image data on the viewing surface, with the scanned image data being read data of the images depicted on the viewing surface, it is necessary to recognize the positional relationship between the scanned image and the projected image.
Accordingly, concerning the above unexamined Japanese Patent Application Publications 2001-16384 and 9-51423, a standard mark is identified by the scanned image data, being read by the image combining apparatus with respect to the image depicted on the viewing surface, so that the positional relationship between the scanned image and the projected image is recognized. However, according to this method, an image to show the standard position is projected from the image projection apparatus, so that a certain mark is projected onto the viewing surface, whereby pictorial figures, being similar to said certain mark, such as a round mark, cannot be used on the board, and if no mark has been applied, the image data cannot be combined, which are adverse matters.
Further, concerning the above unexamined Japanese Patent Application Publication 9-51424, since the positional alignment, between the projected image and the screen, is conducted while the optical sensor mounted on the electronic viewing board is used, a specific electronic viewing board, carrying an optical sensor, is required so that general versatility is very low, which results in an overall increase of system costs.
The present invention has been achieved to overcome the above problems. A main object is to offer an image combining apparatus, by which a positional relationship, between the projected image on the viewing surface and the scanned image being read data of the images depicted on the viewing surface, is easily recognized, so that positional alignment of the images is precisely carried out, and to offer a method for aligning the positions of images.